hfk-bremen.de

Checked 21 October 2026, 22:50 UTC · via 8.8.8.8
✗Problems found
20 passed 1 warning 1 failed 7 info

Registration

info

.de country-code

Found

TLD
.de (country-code)
ICANN policies apply
no

Checks

  • i
    .de is a country-code TLD (ccTLD)
    Country-code TLD: governed by its local registry under national policy, not by an ICANN contract. Registrar accreditation, dispute resolution and RDAP/WHOIS rules are set by the registry.
    #1
  • ✓ TLD delegated and signed #2
    .de is delegated in the root zone and DNSSEC-signed.
  • i
    Registration data not available
    No registration data via RDAP: the registry of .de offers no RDAP service. Many ccTLD registries don't offer RDAP; check the registry's WHOIS instead.
    #3

Delegation

info

deneb.dfn.de, hfk-dnsext01.hfk-bremen.de, hfk-dnsext02.hfk-bremen.de, ines.zfn.uni-bremen.de

Found

Parent zone
de
Delegation from
a.nic.de (194.0.0.53)
NS at the parent
deneb.dfn.de, hfk-dnsext01.hfk-bremen.de, hfk-dnsext02.hfk-bremen.de, ines.zfn.uni-bremen.de
NS in the zone
deneb.dfn.de, hfk-dnsext01.hfk-bremen.de, hfk-dnsext02.hfk-bremen.de, ines.zfn.uni-bremen.de
NameserverAddressesNetwork (AS)Glue
deneb.dfn.de192.76.176.9 2001:638:800:1::9AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE-
hfk-dnsext01.hfk-bremen.de193.175.22.1AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE193.175.22.1
hfk-dnsext02.hfk-bremen.de193.175.22.2AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE193.175.22.2
ines.zfn.uni-bremen.de134.102.20.20 2001:638:708:20::20AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE134.102.20.20 2001:638:708:20::20

Checks

  • ✓ 4 nameservers #6
    Delegated to deneb.dfn.de, hfk-dnsext01.hfk-bremen.de, hfk-dnsext02.hfk-bremen.de, ines.zfn.uni-bremen.de.
  • ✓ Parent and zone agree #7
    The parent delegation and the zone's NS records list the same nameservers.
  • ✓ Glue present and correct #8
    Glue is published for the nameservers inside the zone: hfk-dnsext01.hfk-bremen.de, hfk-dnsext02.hfk-bremen.de.
  • ✓ All names resolve #9
    Every nameserver name has an address and is not an alias.
  • ✓ Nameservers in different networks #10
    The nameservers are spread over 3 IPv4 /24s and 2 IPv6 /48s.
  • i
    All nameservers in one AS
    All nameserver addresses are announced by one network operator (AS680 (DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE): 6 addresses). An outage or attack on that network affects all nameservers; large anycast providers mitigate this, but a secondary DNS provider adds independence.
    #11
  • i
    All nameserver names under .de
    All nameserver names are under one TLD, so a problem with that TLD also makes the nameservers unreachable. Some operators use names under two TLDs for extra resilience.
    #12
  • i
    Partly IPv6
    These nameservers have no IPv6 address: hfk-dnsext01.hfk-bremen.de, hfk-dnsext02.hfk-bremen.de.
    #13

Nameservers

fail

6 of 6 addresses answer authoritatively

Found

NameserverAnswerRecursionTCP / EDNSAXFRVersion
deneb.dfn.de 192.76.176.9NOERROR, 14 ms, authoritativenoyes / yesrefused0
deneb.dfn.de 2001:638:800:1::9NOERROR, 13 ms, authoritativenoyes / yesrefused0
hfk-dnsext01.hfk-bremen.de 193.175.22.1NOERROR, 17 ms, authoritativeOPENyes / yesrefused-
hfk-dnsext02.hfk-bremen.de 193.175.22.2NOERROR, 22 ms, authoritativenoyes / yesrefused-
ines.zfn.uni-bremen.de 134.102.20.20NOERROR, 12 ms, authoritativenoyes / yesrefusedNot supported
ines.zfn.uni-bremen.de 2001:638:708:20::20NOERROR, 12 ms, authoritativenoyes / yesrefusedNot supported

Checks

  • ✓ All respond #14
    All 6 nameserver addresses answered.
  • ✓ All authoritative #15
    Every responding nameserver answers authoritatively for the zone.
  • ✗
    Open recursion
    These nameservers resolve names for anyone, which makes them usable for DNS amplification attacks and cache poisoning: hfk-dnsext01.hfk-bremen.de (193.175.22.1). Disable recursion on authoritative servers.
    #16
  • i
    Identifying string disclosed
    These nameservers answer version queries with a string that is not a version number: deneb.dfn.de: "0"; ines.zfn.uni-bremen.de: "Not supported".
    #17
  • ✓ Zone transfers refused #18
    No nameserver allows a zone transfer to the public.
  • ✓ TCP supported #19
    All nameservers answer over TCP.
  • ✓ EDNS supported #20
    All nameservers support EDNS(0).
  • ✓ Public addresses #21
    All nameserver addresses are publicly routable.

SOA

pass

serial 2019333157 · primary hfk-dnsext01.hfk-bremen.de

Found

Primary (MNAME)
hfk-dnsext01.hfk-bremen.de
Contact (RNAME)
hostmaster.hfk-bremen.de
Serial
2019333157
Refresh / retry
43200 s / 3600 s
Expire
1209600 s
Negative TTL
3600 s

Serial per nameserver

NameserverSerial
deneb.dfn.de (192.76.176.9)2019333157
deneb.dfn.de (2001:638:800:1::9)2019333157
hfk-dnsext01.hfk-bremen.de (193.175.22.1)2019333157
hfk-dnsext02.hfk-bremen.de (193.175.22.2)2019333157
ines.zfn.uni-bremen.de (134.102.20.20)2019333157
ines.zfn.uni-bremen.de (2001:638:708:20::20)2019333157

Checks

  • ✓ Serial 2019333157 everywhere #22
    All nameservers serve the same version of the zone.
  • ✓ Timers within recommendations #23
    SOA refresh 12h, retry 1h, expire 14d, negative TTL 1h.
  • ✓ Primary is a public nameserver #24
    The primary nameserver hfk-dnsext01.hfk-bremen.de is one of the listed nameservers.
  • ✓ Contact hostmaster@hfk-bremen.de #25
    The SOA RNAME hostmaster.hfk-bremen.de means hostmaster@hfk-bremen.de.
  • ✓ Timestamp serial #26
    The serial 2019333157 is a Unix timestamp (2033-12-27 21:52 UTC).

DNSSEC

warn

Not signed

Found

Validated by resolver
no

Checks

  • !
    Not signed
    The zone is not signed with DNSSEC, so answers can be spoofed. Enable DNSSEC at your DNS provider and publish the DS record at your registrar.
    #27

Records

info

14 records at the apex

Found

Read from
192.76.176.9:53
TypeValueTTL
SOAhfk-dnsext01.hfk-bremen.de. hostmaster.hfk-bremen.de. 2019333157 43200 3600 1209600 36003600
NSHFK-DNSEXT02.hfk-bremen.de.3600
NSines.zfn.uni-bremen.de.3600
NSdeneb.dfn.de.3600
NSHFK-DNSEXT01.hfk-bremen.de.3600
A94.130.188.32600
MX0 hfkbremen-de0i.mail.protection.outlook.com.3600
TXT"brevo-code:2d42f819dd97c1574902334ecc7af813"3600
TXT"apple-domain-verification=Idcs2t21po792til"3600
TXT"google-site-verification=ed6XWhT3xJZjD5HVD-jlLF0VXd-QZ3ccWyBeCPT3OP8"3600
TXT"brevo-code:6a7dd92a103a1c5e61527efaaef176e7"3600
TXT"nJ4lletBir1bU67R/1GJVECUpH0PH1aaxPB+7j9JYoAGn+c6WxDREYhQDEB/GrN0o26FD/hrRxrhs6mCrmNsEA=="3600
TXT"adobe-idp-site-verification=5fd3993ead720ca7962d283800931b911285d11de18cfcd4f6c463873c0ba27a"3600
TXT"v=spf1 mx ip4:193.175.22.210 ip4:193.175.22.26 ip4:193.175.22.29 include:spf.protection.outlook.com ~all"3600

Checks

  • ✓ TTLs within range #32
    TTLs: A 10m, MX 1h, NS 1h. The NS TTL at the parent is 1d and in the zone 1h; resolvers may use either.
  • ✓ No CNAME at the apex #33
    The zone apex has no CNAME record.
  • ✓ No wildcard #34
    Names that don't exist return NXDOMAIN.
  • i
    No CAA records
    Without CAA records any certificate authority may issue certificates for this domain. A CAA record limits issuance to the CAs you use.
    #35